Submitted by JOÃO PAULO MENDES TRIBST (joao.tribst@fosjc.unesp.br) on 2017-01-26T19:06:37Z No. of bitstreams: 1 merged (3).pdf: 2530158 bytes, checksum: 8e235a2d5347c6969e7816c0f8e75e91 (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-01-30T19:35:24Z (GMT) No. of bitstreams: 1 tribst_jpm_me_sjc.pdf: 2530158 bytes, checksum: 8e235a2d5347c6969e7816c0f8e75e91 (MD5) / Made available in DSpace on 2017-01-30T19:35:24Z (GMT). No. of bitstreams: 1 tribst_jpm_me_sjc.pdf: 2530158 bytes, checksum: 8e235a2d5347c6969e7816c0f8e75e91 (MD5) Previous issue date: 2017-01-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho buscou estudar as microdeformações geradas ao redor de implantes de hexágono externo durante carregamentos axiais e não axiais, variando-se a angulação dos implantes, utilizando a análise por elementos finitos e a extensometria linear como ferramentas. Inicialmente modelos 3D de diferentes próteses fixas foram construídos a fim de se permitir uma correlação dos resultados encontrados no modelo simplificado com o modelo anatômico e assim validar a geometria da prótese utilizada no estudo. Após a confirmação dos resultados de tensão similar entre as próteses na região dos implantes e do bloco, o modelo da prótese simplificada foi definida como válida. Em seguida, um modelo de bloco de poliuretano foi criado e duplicado. Implantes com conexão de hexágono externo (HE) foram modelados e em um bloco representados perpendiculares à superfície enquanto que em outro bloco foram colocados com inclinação de 17°. Foram modelados também intermediários do tipo mini pilar cônico retos e angulados conforme a inclinação dos implantes. Por último, foi utilizado o modelo de supraestrutura previamente validada para ambos os grupos, na qual a carga foi incidida. Todos os constituintes foram considerados perfeitamente simétricos, sólidos, isotrópicos. Os modelos receberam cargas de 300 N/cm em pontos axiais e não axiais através do software de análise por elementos finitos para se verificar a tensão máxima principal e as microdeformações. Em seguida, através da análise experimental de extensometria, dois blocos de poliuretano foram confeccionados e receberam três HE cada, bem como, respectivos mini pilares cônicos de acordo com a inclinação dos implantes instalados. Então, uma supraestrutura metálica, idêntica ao modelo computacional foi fundida em NiCr e parafusada sobre os implantes com torque de 10 N/cm. Foram aplicadas cargas de 300 N/cm durante 10 segundos em pontos axiais e não axiais. Para mensurar as microdeformações, foram colados quatro extensômetros na superfície de cada bloco tangenciando os implantes. Os dados obtidos foram analisados estatisticamente através dos testes ANOVA e Tukey (α=5%). Os resultados encontrados pela extensometria mostram que existe diferença significante entre o uso de implantes retos ou inclinados (p<0,005) em uma prótese fixa. Através da correlação das metodologias, pode-se observar que o grupo com implantes inclinados atinge picos de tensão acima do limite fisiológico. / This work aimed to study the microstrains generated around external hexagon implants during axial and non-axial loads, varying the angulation of the implants, using finite element analysis and linear strain gauge as tools. Initially 3D models of different fixed prostheses were constructed in order to allow a correlation of the results found in the simplified model with the anatomical model and thus validate the geometry of the prosthesis used in the study. After confirming the results of similar stress between the prostheses in the implants and the block region, the simplified prosthesis was defined as valid. After, a polyurethane block model was created and duplicated. Implants with external hexagon connection (HE) were modeled and inserted perpendiculary into one block while in another block, were placed with the inclination of 17 °. Straight and angled mini conical abutments were also modeled according to the inclination of the implants. Finally, the supra-structure previously validated for both groups was used, through which the load was affected. All constituents were considered perfectly symmetrical, solid, and isotropic. The models received a load of 300 N / cm in axial and non-axial points through the finite element analysis software, to verify the maximum principal stress and microstrains. Then, through the experimental analysis of strain-gauge, two polyurethane blocks were prepared and received three HE implants each, as well as respective mini tapered pillars according to the inclination of the installed implants. Then, a metallic superstructure, identical to the computational model, was cast in Ni-Cr and screwed onto the implants with torque of 10 N / cm. The load of 300 N / cm was applied for 10 seconds at axial and non-axial points. To measure the microstrains, four extensometers were glued on the surface of each block by tangential implants. The data obtained were statistically analyzed using ANOVA and Tukey tests (α = 5%). S strain-gauge data showed that there is a significant difference between using straight or angled implants (p <0.005) in a fixed prosthesis. And, through the correlation of methodologies it can be observed that the group with angled implants reaches peaks of tension above the physiological limit.

Head injuries in American football is a serious issue regarding player health which is highly affected by velocity and its direction. Impact location can affect the severity of the head injury in both helmet-to-helmet impacts and helmet-to-ground impacts hence the understanding of concussive outcome from velocities and impact locations must be improved. In this thesis a video analysis resulted in simulation of five helmet-to-helmet impacts and two helmet-to-ground impacts, where velocity in each impact also was approximated with the method of least squares to avoid extreme values. The average velocity in helmet-to-helmet impacts was 5.1728 m/s for tackler player and 4.4766 m/s for tackled player and in helmet-to-ground impacts it instead was 6.1975 m/s. With the regression method an average velocity of 4.3982 m/s for tackler player and 5.3854 m/s for the tackled player in helmet-to-helmet impacts and 5.874 m/s in helmet-to-ground impacts. The simulations were performed with LS-DYNA and examined in LS-PrePost where head kinematics and the strain of brain tissue or more specific the maximum principal strain (MPS) was of interest. Further the MPS was scaled to its 95th percentile which determined the concussive likelihood for each impact scenario. The highest concussive outcome for an impact scenario was 100% and the lowest was 15%. The head kinematics of interest was linear acceleration, angular acceleration and angular velocity which in high risk for concussive outcome wasn't dominated by a single head kinematic. Impacts locations in helmet-to-helmet impacts didn't show any connection between impact location and high concussive risk. In helmet-to-ground impacts a connection between impact location at the back of the head and high concussive risk was observed. / Huvudskador inom Amerikansk fotboll är ett återkommande problem när det gäller spelarnas hälsa. Hastigheten och vart tacklingen träffar är starkt kopplat till hur allvarlig en huvudskada kan bli i både hjälm-mot-hjälm tacklingarn och hjälm-mot-mark. För att förhindra huvudskador måste förståelsen om kinematiken och vart tacklingen träffar förbättras.  I detta examensarbete gjordes en videoanalys vilket resulterade i fem hjälm-mot-hjälm simuleringar och två hjälm-mot-mark. Hastigheten approximerades också genom att använda uppskattnings metoden minsta kvadratmetoden. Medel-värdet av hastigheterna från videoanalysen blev 5.1728 m/s för spelaren som utförde tacklingen och 4.4766 m/s för spelaren som blev tacklad i hjälm-mot-hjälm tacklingar. I hjälm-mot-mark blev det istället ett medelvärde på 6.1975 m/s. Med uppskattnings metoden blev hastigheterna istället 4.3982 m/s för den tacklande spelaren och 5.3854 m/s för den tacklade spelaren i hjälm-mot-hjälm tacklingar. För hjälm-mot-mark blev medelvärdet av hastigheten 5.874 m/s med uppskattnings metoden. Simuleringarna av tacklings fallen gjordes med LS-DYNA och analyserades i LS-PrePost där huvudets kinematik och töjningen av hjärnvävnad är av intresse. Töjningen mättes av maximum principal strain (MPS) och den 95:e percentilen av MPS för att bestämma risken för hjärnskakning där den största risken för hjärnskakning var 100% och den minsta 15%. För huvudets kinematik var det linjär acceleration, vinkelacceleration och vinkelhastighet som var av intresse. Det fanns ingen koppling mellan endast en av kinematikerna och hög risk för hjärnskakning. Gällande vart tacklingen träffar fanns det ingen koppling mellan vart den träffar och hög risk för hjärnskakning i hjälm-mot-hjälm tacklingar. För hjälm-mot-mark tacklingar fanns det ett samband mellan att bakre delen av huvudet träffar marken och hög risk för hjärnskakning.

This thesis focuses on the effect of microstructural variation on the mechanical properties and deformation behavior of ductile iron. To research and determine these effects, two grades of ductile iron, (i) GJS-500-7 and (ii) high silicon GJS-500-14, were cast in a geometry containing several plates with different section thicknesses in order to produce microstructural variation. Microstructural investigations as well as tensile and hardness tests were performed on the casting plates. The results revealed higher ferrite fraction, graphite particle count, and yield strength in the high silicon GJS-500-14 grade compared to the GJS-500-7 grade. To study the relationship between the microstructural variation and tensile behavior on macroscale, tensile stress-strain response was characterized using the Ludwigson equation. The obtained tensile properties were modeled, based on the microstructural characteristics, using multiple linear regression and analysis of variance (ANOVA). The models showed that silicon content, graphite particle count, ferrite fraction, and fraction of porosity are the major contributing factors that influence tensile behavior. The models were entered into a casting process simulation software, and the simulated microstructure and tensile properties were validated using the experimental data. This enabled the opportunity to predict tensile properties of cast components with similar microstructural characteristics. To investigate deformation behavior on micro-scale, a method was developed to quantitatively measure strain in the microstructure, utilizing the digital image correlation (DIC) technique together with in-situ tensile testing. In this method, a pit-etching procedure was developed to generate a random speckle pattern, enabling DIC strain measurement to be conducted in the matrix and the area between the graphite particles. The method was validated by benchmarking the measured yield strength with the material’s standard yield strength. The microstructural deformation behavior under tensile loading was characterized. During elastic deformation, strain mapping revealed a heterogeneous strain distribution in the microstructure, as well as shear bands that formed between graphite particles. The crack was initiated at the stress ranges in which a kink occurred in the tensile curve, indicating the dissipation of energy during both plastic deformation and crack initiation. A large amount of strain localization was measured at the onset of the micro-cracks on the strain maps. The micro-cracks were initiated at local strain levels higher than 2%, suggesting a threshold level of strain required for micro-crack initiation. A continuum Finite Element (FE) model containing a physical length scale was developed to predict strain on the microstructure of ductile iron. The material parameters for this model were calculated by optimization, utilizing the Ramberg-Osgood equation. The predicted strain maps were compared to the strain maps measured by DIC, both qualitatively and quantitatively. To a large extent, the strain maps were in agreement, resulting in the validation of the model on micro-scale. In order to perform a micro-scale characterization of dynamic deformation behavior, local strain distribution on the microstructure was studied by performing in-situ cyclic tests using a scanning electron microscope (SEM). A novel method, based on the focused ion beam (FIB) milling, was developed to generate a speckle pattern on the microstructure of the ferritic ductile iron (GJS-500-14 grade) to enable quantitative DIC strain measurement to be performed. The results showed that the maximum strain concentration occurred in the vicinity of the micro-cracks, particularly ahead of the micro-crack tip. / Denna avhandling fokuserar på effekten av variationer i mikrostrukturen på mekaniska egenskaper och deformationsbeteende hos segjärn. För att undersöka dessa effekter, två olika sorter av segjärn, (i) GJS-500-7 och (ii) högkisellegerad GJS-500-14, gjutits till plattor av olika tjocklekar för att generera mikrostrukturvariationen. Mikrostrukturundersökning, samt drag- och hårdhetsprov gjordes på de gjutna plattorna. Resultaten visade att en högre ferritfraktion, grafitpartikelantal och sträckgräns i den högkisellegerade GJS-500-14-sorten jämfört med GJS-500-7. För att studera förhållandet mellan mikrostrukturell variation och spännings-töjningsbeteendet på makroskala, modellerades detta med hjälp av Ludwigson-ekvationen. De erhållna spännings-töjningsegenskaperna modellerades baserat på mikrostrukturell karaktäristika genom multipel linjärregression och variansanalys (ANOVA). Modellerna visade att kiselhalt, grafitpartikelantal, ferritfraktion och porfraktion var de viktigaste bidragande faktorerna. Modellerna implementerades i ett simuleringsprogram för gjutningsprocessen. Resultatet från simuleringen validerades med hjälp av experimentella data som inte ingick i underlaget för regressionsanalysen. Detta möjliggjorde att prediktera spännings-töjningsbeteendet och dess variation hos gjutna segjärns komponenter med liknande sammansättning och gjutna tjocklekar som användes i denna studie. För att kunna undersöka deformationsbeteendet på mikroskala utvecklades en metod för kvantitativ mätning av töjning i mikrostrukturen, genom DIC-tekniken (digital image correlation) tillsammans med in-situ dragprovning. I denna metod utvecklades en grop-etsningsprocess för att generera ett slumpvis prickmönster, vilket möjliggjorde DIC-töjningsmätning i matrisen och i området mellan grafitpartiklarna med tillräcklig upplösning. Metoden validerades genom benchmarking av den uppmätta sträckgränsen mot materialets makroskopiska sträckgräns mätt med konventionell dragprovning. Det mikrostrukturella deformationsbeteendet under dragbelastning karakteriserades. Under elastisk deformation avslöjade töjningsmönstret en heterogen töjningsfördelning i mikrostrukturen, och bildandet av skjuvband mellan grafitpartiklar. Sprickbildning initierades vid låg spänning och redan vid de spänningsnivåer som ligger vis ”knät” på dragprovningskurvan, vilket indikerar energidissipering genom både begynnande plastisk deformation och sprickbildning. Den lokala töjningen vis sprickinitiering skedde då den lokala töjningen översteg 2%, vilket indikerar att detta skulle kunna vara en tröskelnivå för den töjning som erfordras för initiering av mikro-sprickor. En kontinuum Finita Element (FE) modell utvecklades för att prediktera töjningen hos ett segjärn och dess fördelning i segjärns mikrostruktur. Materialparametrarna för denna modell optimerades genom att anpassa parametrarna i Ramberg-Osgood ekvationen. De predikterade töjningsfördelningarna jämfördes med de experimentell uppmätta töjningsmönstren uppmätta med DIC, både kvalitativt och kvantitativt. Töjningsmönstren överensstämde i stor utsträckning, vilket resulterade i att modellerna kunde anses vara validerade på mikronivå. För att kunna mäta töjningsmönster under dynamiska förlopp på mikronivå utvecklades en metod för att skapa prickmönster och att utföra in-situ CT provning i ett svepeletronmikroskop (SEM). Prickmönstret skapades genom avverkning med en fokuserad jonstråle (FIB), och provades på det ferritiska segjärnet (GJS-500-14 grad). Resultaten visade att maximal töjningskoncentration fanns i närheten av mikrosprickorna, framförallt framför sprickspetsen.

When developing three-phase drives for Electric Vehicles (EVs), it is essential to verify the controller design. This will help in understanding how fast and accurately the torque of the motor can be controlled. In order to do this, it is always better to test the controller using the software version of the motor or vehicle drivetrain than using actual hardware as it could lead to component damage when replicating extreme physical behavior. In this thesis, plant modelling of Permanent Magnet Synchronous Machine (PMSM) and vehicle drivetrain in MATLAB/Simulink for Model Based Design (MBD) is presented. MBD is an effective method for controller design that, if adopted can lead to cost savings of 25%-30% and time savings of 35%-40% (according to a global study by Altran Technologies, the chair of software and systems engineering and the chair of Information Management of the University of Technology in Munich) [1]. The PMSM plant models take effects like magnetic saturation, cross- coupling, spatial harmonics and temperature into account. Two PMSM models in d-q frame based on flux and inductance principles were implemented. Flux, torque maps from Finite Element Analysis (FEA) and apparent inductance from datasheets were used as inputs to the flux- and inductance-based models, respectively. The FEA of PMSM was done using COMSOL Multiphysics. The PMSM model results were compared with corresponding FEA simulated results for verification. A comparison of these PMSM models with conventional low fidelity models has also been done to highlight the impact of inclusion of temperature and spatial harmonics. These motor models can be combined with an inverter plant model and a controller can be developed for the complete model. Low frequency oscillations of drivetrain in EVs lead to vibrations which can cause discomfort and torsional stresses. In order to control these oscillations, an active oscillation damping controller can be implemented. For implementation of this control, a three-mass mechanical plant model of drivetrain with an ABS (Anti-lock Braking System) wheel speed sensor has been developed in this thesis. Analysis of the model transfer function to obtain the pole zero maps was performed. This was used to observe and verify presence of low frequency oscillations in the drivetrain. In order to include the effects of ABS wheel speed sensor and CAN communication, a model was developed for the sensor. / Testning av regulatorernas inställningar med hänsyn till snabbhet och noggrannhet i momentreglering är avgörande i trefasiga drivsystem för elektriska fordon. Oftast är det bättre att simulera i stället för att utföra experimentella tester där komponenter kan skadas på grund av fysisk stress. Detta kallas för Model Based Design (MBD). MBD är an effektiv metod för utformningen av styrningen som kan leda till kostnadsbesparingar på 25%-30% och tidsbesparingar på 35%-40% enligt en studie från Altran Technologies i samarbete med Tekniska universitet i München, TUM. Detta examensarbete behandlar en modell för en synkronmaskin med permanentmagneter (PMSM) samt en modell för drivlinan utvecklad i Matlab/Simulink för MBD. PMSMs modellen inkluderar magnetisk mättnad och tvärkoppling, MMF övervågor och temperatur. Två PMSM modeller har utvecklats. Den första baseras på magnetiskt flöde som erhålls från finita element beräkningar i COMSOL Multiphysics medan den andra bygger på induktanser givna från datablad. En jämförelse av dessa PMSM-modeller med konventionella low fidelity-modeller har också gjorts för att illustrera påverkan temperaturberoende och MMF övervågor. Modellerna kan kombineras med en växelriktarmodell för att utveckla en hel styrenhet. Lågfrekventa oscillationer i drivlinan leder till vibrationer som kan orsaka vridspänningar och försämra komforten i elfordonet. En aktiv dämpningsregulator kan implementeras för att kontrollera spänningarna men en mekanisk drivlinemodell med tre massor och en ABS (anti-lock braking system) hastighetssensor behövs. Den mekaniska modellen har implementerats och analyserats även beaktande en modell för en CAN kommunikationskanal. Oscillationer med låg frekvens kunde observeras i modellen.